Affinities.Baetis aureus
exhibits the main characters of the
B. vernus
and
B. buceratus
species groups sensu
Mueller-Liebenau
(1969)
and cannot be assigned to any of them with certainty. Therefore, it is compared here to species of both species groups. Characters typical to both groups include mandibles with bigger outer tooth, labrum with submarginal arc of less than eight setae, tarsal claws without subapical setae, distal margin of abdominal terga with triangular spines, relatively long gills, and generally inconspicuous pattern of the terga (
Bauernfeind and
Soldan
2012
).
Baetis aureus
differs from all known species of these two species groups by the median caudal filament that is slightly longer than half the length of its cerci (whereas in other species the median caudal filament is almost as long as the cerci, except in
B. zdenkaeSoldan
& Godunko, 2009), and by the small size of the scale bases on the surface of the abdominal terga.
In the
B. vernus
species group, seven species were reported from the West Palearctic region, and differ from
B. aureus
as follows:
Baetis vernus
Curtis, 1834 has a mola with two small auxiliary spines at the outer side of the subtriangular process (figure 91 in
Eiseler 2005
). In
B. liebenauaeKeffermueller
, 1974 the outer sets of incisors in the mandibles are fused, and the spines on the distal margin of terga are blunt and rounded (
Keffermueller
1974
). In
B. macrospinosus
Koch, 1985 the setae on the dorsal margin of femora are longer and apically rounded, terga are covered with abundant scale bases, spines on distal margin of terga are blunt and rounded, and dorsal pattern of abdomen is well-marked (
Koch 1985
). In
B. macani
Kimmins, 1957 the distolateral protuberance on segment II of the labial palpus (
"thumb"
) is considerably developed (
Mueller-Liebenau
1969
). The gill tracheation of
B. tracheatusKeffemueller
& Machel, 1967 is conspicuous. The submarginal arc of setae on the labrum of
B. tracheatus
and
B. subalpinus
Bengtsson, 1917 is reduced to 2-3 setae (
Mueller-Liebenau
1969
). Finally,
B. samochai
Koch, 1981 is characterized by long and sharp spines along the distal margin of terga, its maxillary palpus is longer than the galealacinia, and the dorsal pattern on its abdomen is different (
Koch 1981
).
Baetis aureus
differs from all other known species of the
B. buceratus
species group (see
Soldan
and Godunko 2009
) as follows: in
B. buceratus
Eaton, 1870, the submarginal distal arc on the labrum consists of only 3 setae, and spines on the distal margin of terga are narrow and blunt (
Mueller-Liebenau
1969
). In
B. spei
Thomas & Dia, 1985, a geographically close relative from Lebanon, the shape of the labial palpus is different, teeth on the outer set of the left mandible incisor are wider, spines on the distal margin of terga are rounded and blunt, marginal spines on paraproct are irregular and of variable shapes (
Thomas and Dia 1985
). In
B. pentaphlebodes
Ujhelyi, 1966 segment III of the labial palpus is shorter (compared to segment II). In
B. zdenkae
from Rhodes, Greece, the incisors of the right mandible are not arranged in a decreasing size order, more setae are present on the paraglossa base, and less marginal spines are found on the paraproct (
Soldan
and Godunko 2009
). Finally, in
B. monnerati
the setae on the dorsal margin of femora are long, and the gills are oval (
Gattolliat et al. 2012
).
Etymology.Aureus
(Latin for golden) refers to the general colour of the nymph body.
Distribution and ecology.
This species is common in the northern regions of Israel: Lower and Upper Galilee, Hula Valley and Golan Heights, and rare in the Yarqon stream. It is found in habitats of running, pristine water, particularly in small creeks but also in larger streams such as the Keziv and Zippori (Figure 2C, E, F). The substrate is usually composed of stones of different sizes, and localities with dense submerged vegetation are preferred. Mature nymphs were collected mostly in spring (
March-May
) and fall (
October-November
).
Material examined.
Holotype. ISRAEL: 1 Nymph, Gamla Stream (Peham Springs),
32.9672°N
,
35.8201°E
, ca 690 m a.s.l., 04.iv.2016, Z. Yanai, SMNHTAU291999. Paratypes. ISRAEL: 88N, Barqan Stream, 25.v.2011, Y. Hershkovitz; 1N, Gilbon Stream (upstream Devora Waterfall), 09.iv.2014, Z. Yanai; 1N, Yarqon Stream (national park), 10.iv.2014, Z. Yanai; 4N (1N on slide), Ammud Stream (Yaqim Spring), 20.v.2014, Z. Yanai; 1N, Fit Spring, 10.vi.2014, Z. Yanai; 9N (2N on slides), Gaaton Junction, 17.vi.2014, Z. Yanai & D. Mayer; 3N, Zippori Stream (Ras Ali), 02.iii.2015, Z. Yanai; 1N, Gilbon Stream (upstream Devora Waterfall), 29.x.2015, Z. Yanai & Y. Brenner; 107N (1N on slide), Keziv Stream (Hardalit Spring), 07.xi.2015, Z. Yanai & S. Cohen; 17N, Keziv Stream (Tamir Spring), 07.xi.2015, Z. Yanai & S. Cohen; 1N, Zippori Stream (Zippori Springs), 07.xi.2015, Z. Yanai & S. Cohen; 40N, Zippori Stream (Ras Ali), 07.xi.2015, Z. Yanai & S. Cohen; 19N, Gamla Stream (Peham Springs), 04.iv.2016, Z. Yanai; 154N (1N on slide), Zippori Stream (Zippori Springs), 19.iv.2016, Z. Yanai; 24N (1N on slide), Rosh
Pinna
Stream (Rosh
Pinna
), 15.x.2016, Z. Yanai; 6N, Yarqon Stream, 14.v.2017, Y. Hershkovitz. Other material. ISRAEL: 4N, Zippori Stream (Yivqa Spring), 21.ii.2014, Z. Yanai; 5N (1N on slide), Keziv Stream (Hardalit Spring), 17.vi.2014, Z. Yanai & D. Mayer; 4N, Ammud Stream (Poem Spring), 18.v.2015, Y. Hershkovitz & T. Eshcoly.